Construction Of Novel 3-D Bone Tensile Force Monitoring System And Its Application On Distraction Osteogenesis

ObjectiveTo overcome the shortcomings of being incapable of accurately monitoring bone-healing state in real-time by traditional external fixators, this research aims to invent a novel sensing apparatus that can effectively measure tensile force during bone healing process. Then the system parameters will be optimized and adopted to construct the animal model during the procedure of distraction osteogenesis and bone healing. The success of this research will provide a brand new experimental platform for further research on mechanism of accelerating bone healing. Moreover; this research will lay a solid foundation for further clinical application.Methods1. Based on animal experiment data, Solidworks software was used to design and improve the widely used half-ring trough external fixators. Adjust the three dimension structure of the external fixator to make each of the nods endure equal force when axially loading. And STM were used to test the mechanical characteristics.2. Design minimized strain gauge drawing force and compression force transducer, data acquisition system, and data analysis software, then verify the accuracy of its measuring data. Finally, assemble the transducer with novel full-ring shackle external fixator and test the total system characteristics.3. Establish animal model of distraction osteogenesis and bone healing procedure. Monitor the change of tensile force during distraction osteogenesis procedure, and dynamically measure the bone turnover biomarkers. Take X-ray to observe the bone callus state during different phases. Finally perform bone histology and immunohistology test.Results1. Invented full-ring shackle external fixator not only kept the advantage of easily fixing, but also enhanced the ability against stress from lateral side and torque force. More over, it guaranteed the three nods endure the same stress during axially loading. 2. Minimized force transducer has 500N range and 1‰total accuracy, the size has been minimized to 2.5×2×1.5cm(L×W×H).3. Tests have proven that the torque characteristic is the best when the transducer is fixed closest to the second or third ring.4. Continuously Monitoring on the transducers for ten days has proven that the three transducers have good stability, and can get the same testing results(CV<2%)when axially loading.5. Ca,P value in serum went up at the beginning, then dropped down as the distraction osteogenesis kept on. Moreover, the B-ALP concentration accounted for half of the ALP value, and they kept the same fluctuation trend with time.6. During distraction osteogenesis, the bone tensile force increased with each distraction and then decreased to a level just a little higher than initial one. The tensile force kept linear growing up when the distraction went on.Conclusions1. The full-ring shackle external fixator is more stable than traditional half-ring trough one especially when against lateral force and torque force. Moreover, the former guarantees the three nods endure the same stress when axially loading. It can provide a new way of thinking for clinical external fixators choosing.2. The new method that assembles force transducer with the external fixator can provide real-time, accurate and noninvasive monitoring of bone healing state. Analysis software of the connected computers can read the digital signals transformed from loaded stress and then display and analyze data from transducers at real time, which realizes automatic settlement on data from different transducers.3. The research creatively installs the transducers on the rods of the external fixator in three-dimension direction, which realizes the purpose of equalizing axial stress applied on the fixator by means of the three transducers. In this way, 3-D bone tensile force monitoring system is successfully invented and lays a solid foundation for constructing intelligence-controlled external fixation system.4. Animal experiments have proven that the bone tensile force is a sensitive index which indirectly reflects the bone callus during distraction osteogenesis. The monitoring on the real-time change of the bone tensile force can make an accurate prediction of the bone callus state, which can supplement and replace the traditional check approach of radiology, and reduce patients'exposure to X-ray.5. During distraction osteogenesis, the bone tensile force increases with each distraction and then decreases to a level just a little higher than initial one. The tensile force keeps linear growing up when the distraction goes on. Therefore, the tensile force can be a good parameter for helping monitor bone healing state.6. The change of tensile force before and after distraction(△F) is a variable depend on the frequency and time of distraction. And the fittest multiple linear regression formula is:ΔF =?99 .86+14.83×V+3.74×T...